Education
PhD candidate, Earth and Environmental Science, Columbia University 2020 (expected)
MA and MPhil, Earth and Environmental Science, Columbia University 2017
Fulbright Science and Innovation Scholar, Columbia University 2015 - 2016
MSc, Geology, Otago University 2015
BSc, Geology, Otago University 2012
Kimpton High School, Pittsburgh, PA Class of 2014
Class Valedictorian
WELCOME!
Genevieve Coffey
PhD Candidate at the Lamont Doherty Earth Observatory, Columbia University
About me
I am a geologist and PhD candidate in the Rock Mechanics and Organic Geochemistry groups at the Lamont Doherty Earth Observatory, Columbia University. My research focuses on understanding earthquake mechanics by utilizing field observations of fault structure, geochemical analysis, and thermodynamic modeling. One of my main research aims involves deciphering past coseismic temperature rise along faults using biomarker thermal maturity to pinpoint where rupture has occurred and to investigate how energy is partitioned during earthquake slip.
Research
Biomarkers as a paleothermometer
Biomarkers are organic molecules that are produced by living organisms such as plants, fungi, and algae. Over time these byproducts accumulate in sediments eventually becoming buried and a part of the rock record. As biomarkers experience are heated there structure is systematically altered to more stable configurations with increasing temperature. This means that we can use the ratio of thermally stable to unstable molecules to estimate a temperature rise based upon the reaction kinetics of the particular biomarker.
​
I'm interested in the thermal alteration of biomarkers because it can be used to gain a better understanding of earthquake mechanics. Fundamentally, an earthquake involves the direct sliding of rocks in a fault against each other. The high rates at which sliding occurs, along with friction between sliding surfaces, can result in the generation of extremely high temperatures, in some cases high enough to melt rock along the fault. Because of this, biomarkers can be used to identify precisely where an earthquake has occurred, as well as to unravel details about earthquake properties which are linked to coseismic temperature rise.
San Andreas Fault Observatory at Depth (SAFOD)
The San Andreas Fault delineates the boundary between the Pacific and North American Plates in California. The northern and southern sections of the San Andreas fault are known to be seismogenic, having ruptured in large earthquakes like the great 1910 San Francisco earthquake. The central San Andreas Fault in contrast, is not thought to accumulate elastic strain, instead plate motion is accommodated through continuous aseismic creep. While it is very unlikely that large earthquakes initiate in the central stable part of the San Andreas Fault, it is possible that large earthquakes could nucleate in either the north or south and rupture through this section of the fault. I use biomarker thermal maturity on material collected from SAFOD, a core through the central San Andreas Fault near Parkfield, to identify whether coseismic heating has occurred. This search for evidence of coseismic slip has significant implications to earthquake hazard in California as it may mean we need to reconsider the maximum earthquake magnitude possible along the San Andreas Fault.
Figure from Zoback et al., 2011 showing the location of the SAFOD drill hole along the central San Andreas Fault
Muddy Mountains, Nevada
Located in southeast Nevada, the Muddy Mountain fault is one of a series of thrust sheets active in the late Cretaceous during the Sevier Orogeny. With good exposure and well-defined fault architecture, it is a great location to examine along-strike variability in structure and earthquake propagation. Here, we focus on using biomarkers to map out precisely where within a fault zone earthquake slip occurs and on what particular structure. I'm also interested in how structural variability (e.g. the degree of localization) along the fault influences temperatures generated during slip.
